KR102579269B1 - adhesive film - Google Patents

Abstract

In one form of the present invention, a first adhesive layer, a metal layer, and a second adhesive layer are provided in this order, and each of the first adhesive layer and the second adhesive layer is a dendrite-shaped conductive particle. and an adhesive film containing second conductive particles, which are conductive particles other than the first conductive particles and are conductive particles having a non-conductive nuclide and a conductive layer provided on the nuclide.

Description

adhesive film

The present invention relates to adhesive films.

In recent years, various adhesives have been used in fields such as semiconductors and liquid crystal displays to secure electronic components and connect circuits. In these applications, electronic components, circuits, etc. are becoming more dense and precise, and adhesives are also required to have higher levels of performance.

For example, in the connection between a liquid crystal display and a TCP (Tape Carrier Package), the connection between an FPC (Flexible Printed Circuit) and TCP, or the connection between an FPC and a printed wiring board, the conductive adhesive is used. Adhesives with dispersed particles are used. These adhesives are required to further improve conductivity and reliability between adherends.

For example, Patent Document 1 describes a conductive film provided with a conductive film containing predetermined dendrite-like silver-coated copper powder particles on a base film, and such a conductive film provides sufficient film even without mixing silver powder. It is disclosed that conductive properties are obtained.

International Publication No. 2014/021037

However, in recent years, depending on the application target of the adhesive film, an adhesive film thicker than usual (for example, 40 μm or more) is required. According to the present inventors' examination, in this case, the desired properties are not necessarily obtained simply by thickening the conventional adhesive film. When the conventional adhesive film is merely thickened, there is room for improvement in terms of conductivity when, for example, electronic members are connected to each other at low pressure (for example, 0.1 to 0.5 MPa). On the other hand, it is conceivable to secure conductivity (lower than a predetermined connection resistance) by increasing the pressure when connecting electronic members, but in this case, there is a risk that the adhesive component (resin component) will extrude between the electronic components and leak out. There is.

Therefore, the purpose of the present invention is to provide an adhesive film that is excellent in conductivity during low-pressure connection and can suppress leakage of the adhesive during connection.

In one form of the present invention, a first adhesive layer, a metal layer, and a second adhesive layer are provided in this order, and each of the first adhesive layer and the second adhesive layer is a dendrite-shaped conductive particle. and an adhesive film containing second conductive particles, which are conductive particles other than the first conductive particles and are conductive particles having a non-conductive nuclide and a conductive layer provided on the nuclide.

The conductive layer preferably contains at least one member selected from the group consisting of gold, nickel, and palladium.

The thickness of the metal layer is preferably 25 μm or more. The thickness of the first adhesive layer is preferably 30 μm or less. The thickness of the second adhesive layer is preferably 30 μm or less.

According to the present invention, it is possible to provide an adhesive film that is excellent in conductivity during low-pressure connection and can suppress leakage of the adhesive during connection.

1 is a schematic cross-sectional view showing one embodiment of an adhesive film.
Fig. 2 is a cross-sectional view of the main part schematically showing an example of connection between electronic members.
Fig. 3 is a schematic diagram showing a method of manufacturing a mounting body for evaluation in an example.
Fig. 4 is a schematic diagram showing a method for measuring connection resistance in an example.

Hereinafter, embodiments of the present invention will be described in detail with appropriate reference to the drawings.

1 is a schematic cross-sectional view showing one embodiment of an adhesive film. As shown in FIG. 1, the adhesive film 1 includes a first adhesive layer 2, a metal layer 3, and a second adhesive layer 4 in this order. The first adhesive layer (2) and the second adhesive layer (4) each contain an adhesive component (5) and first conductive particles (6) and second conductive particles (7) dispersed in the adhesive component (5). do.

Hereinafter, the first adhesive layer 2 and the second adhesive layer 4 (hereinafter, these are also collectively referred to as “adhesive layers 2 and 4”) will be described. The structures of the first adhesive layer 2 and the second adhesive layer 4 may be the same or different from each other.

The adhesive component 5 is composed of a material that exhibits curability by heat or light, for example, and may be an epoxy adhesive, a radically curable adhesive, a thermoplastic adhesive containing polyurethane, polyvinyl ester, or the like. The adhesive component 5 may be composed of a crosslinkable material because it is excellent in heat resistance and moisture resistance after adhesion. Epoxy-based adhesives contain epoxy resin, which is a thermosetting resin, as a main component. Epoxy-based adhesives are preferably used because they can be cured in a short time, have good connection workability, and have excellent adhesive properties. Radical curing type adhesives have characteristics such as superior curing properties at low temperatures and in a short time compared to epoxy adhesives, so they are appropriately used depending on the application.

The epoxy adhesive contains, for example, an epoxy resin (thermosetting material) and a curing agent, and may further contain a thermoplastic resin, a coupling agent, a filler, etc., if necessary.

As epoxy resins, for example, bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenol S-type epoxy resin, phenol novolak-type epoxy resin, cresol novolak-type epoxy resin, bisphenol A novolak-type epoxy resin, bisphenol F. Examples include novolak-type epoxy resin, alicyclic epoxy resin, glycidyl ester-type epoxy resin, glycidylamine-type epoxy resin, hydantoin-type epoxy resin, isocyanurate-type epoxy resin, and aliphatic chain epoxy resin. . These epoxy resins may be halogenated, may be hydrogenated, or may have a structure in which an acryloyl group or a methacryloyl group is added to the side chain. These epoxy resins are used individually or in combination of two or more types.

The curing agent is not particularly limited as long as it can cure the epoxy resin, and examples include anionic polymerizable catalyst-type curing agents, cationic polymerizable catalyst-type curing agents, and polyaddition-type curing agents. Among these, anionic or cationic polymerizable catalyst-type curing agents are preferred because they are excellent in rapid curing properties and do not require consideration of chemical equivalents.

Examples of anionic or cationic polymerizable catalyst-type curing agents include imidazole, hydrazide, boron trifluoride-amine complex, onium salts (aromatic sulfonium salts, aromatic diazonium salts, aliphatic sulfonium salts, etc.), amine imides, diazonium salts, etc. Examples include minomaleonitrile, melamine and its derivatives, polyamine salts, dicyandiamide, etc., and modified products thereof can also be used. Examples of polyaddition type curing agents include polyamines, polymer captans, polyphenols, and acid anhydrides.

These curing agents may be latent curing agents coated with polymer materials such as polyurethane or polyester, thin films of metals such as nickel or copper, or inorganic substances such as calcium silicate, and then microencapsulated. A latent hardener is preferable because it can extend the pot life. The hardening agent is used individually or in combination of two or more types.

The content of the curing agent may be 0.05 to 20 parts by mass with respect to 100 parts by mass of the total amount of the thermosetting material and the thermoplastic resin mixed as necessary.

A radically curable adhesive contains, for example, a radical polymerizable material and a radical polymerization initiator (also called a curing agent), and may further contain a thermoplastic resin, a coupling agent, a filler, etc., if necessary.

As a radically polymerizable material, for example, any material having a functional group that polymerizes by radicals can be used without particular restrictions. Specifically, for example, acrylate (including the corresponding methacrylate. The same applies hereinafter) compound, acrylic oxygen (also includes the corresponding methacryloxy. The same applies hereinafter) compound, maleimide compound, Radical polymerizable materials such as citraconimide resin and nadiimide resin can be mentioned. These radically polymerizable materials may be in the form of monomers or oligomers, or may be in the form of a mixture of monomers and oligomers.

Examples of acrylate compounds include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, and tetramethylol. Methane tetraacrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxymethoxy)phenyl]propane, 2,2-bis[4-(acryloxypolyester) Toxy)phenyl]propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris(acryloyloxyethyl)isocyanurate, urethane acrylate, and phosphoric acid ester diacrylate.

Radical polymerizable materials such as acrylate compounds may be used together with polymerization inhibitors such as hydroquinone and methyl ether hydroquinone, as needed. From the viewpoint of improving heat resistance, radically polymerizable materials such as acrylate compounds preferably have at least one substituent such as a dicyclopentenyl group, tricyclodecanyl group, or triazine ring. As a radically polymerizable material other than an acrylate compound, it is possible to suitably use, for example, a compound described in International Publication No. 2009/063827. Radical polymerizable materials are used individually or in combination of two or more types.

As a radical polymerization initiator, for example, any compound that is decomposed by heating or irradiation of light to generate free radicals can be used without particular limitation. Specifically, examples include peroxide compounds and azo compounds. These compounds are appropriately selected depending on the intended connection temperature, connection time, potable time, etc.

As a radical polymerization initiator, more specifically, diacyl peroxide, peroxydicarbonate, peroxy ester, peroxy ketal, dialkyl peroxide, hydroperoxide, silyl peroxide, etc. can be mentioned. Among these, peroxyesters, dialkyl peroxides, hydroperoxides, silyl peroxides, etc. are preferable, and peroxyesters that achieve high reactivity are more preferable. As these radical polymerization initiators, it is possible to suitably use, for example, the compounds described in International Publication No. 2009/063827. The radical polymerization initiator is used individually or in combination of two or more types.

The content of the radical polymerization initiator may be 0.1 to 10 parts by mass with respect to 100 parts by mass of the total amount of the radical polymerizable material and the thermoplastic resin blended as necessary.

In epoxy-based adhesives and radically curable adhesives, thermoplastic resins blended as needed make it easy to mold the adhesive into a film, for example. Thermoplastic resins include, for example, phenoxy resin, polyvinyl formal resin, polystyrene resin, polyvinyl butyral resin, polyester resin, polyamide resin, xylene resin, polyurethane resin, polyester urethane resin, phenol resin, Terpene phenol resin, etc. can be mentioned. As a thermoplastic resin, it is possible to suitably use, for example, a compound described in International Publication No. 2009/063827. Among these, phenoxy resin is preferable because it is excellent in adhesiveness, compatibility, heat resistance, mechanical strength, etc. Thermoplastic resins are used individually or in combination of two or more types.

When blended in an epoxy-based adhesive, the content of the thermoplastic resin may be 5 to 80 parts by mass based on 100 parts by mass of the total amount of the thermoplastic resin and thermosetting material. When blended in a radically curable adhesive, the content of the thermoplastic resin may be 5 to 80 parts by mass based on 100 parts by mass of the total amount of the thermoplastic resin and the radically polymerizable material.

Another example of the adhesive component (5) is a thermal radical curing adhesive containing a thermoplastic resin, a radically polymerizable material that is liquid at 30°C, and a radical polymerization initiator. The thermal radical curing type adhesive has a low viscosity compared to the adhesives described above. The content of the radically polymerizable material in the thermal radically curable adhesive is preferably 20 to 80 parts by mass, more preferably 30 to 80 parts by mass, based on 100 parts by mass of the total amount of the thermoplastic resin and the radically polymerizable material. Preferably it is 40 to 80 parts by mass.

The adhesive component 5 may be an epoxy-based adhesive containing a thermoplastic resin, a thermosetting material containing an epoxy resin that is liquid at 30°C, and a curing agent. In this case, the content of the epoxy resin in the epoxy adhesive is preferably 20 to 80 parts by mass, more preferably 40 to 80 parts by mass, and still more preferably 100 parts by mass of the total amount of the thermoplastic resin and thermosetting material. is 30 to 80 parts by mass.

When the adhesive film 1 is used to connect an IC chip, a glass substrate, a flexible printed circuit board (FPC), etc., from the viewpoint of suppressing warpage of the substrate due to the difference in linear expansion coefficient between the IC chip and the substrate, the adhesive component ( 5) Preferably, it further contains a component that exerts an internal stress relieving effect. Specific examples of such components include acrylic rubber and elastomer components. Alternatively, the adhesive component 5 may be a radical curing type adhesive described in International Publication No. 98/44067.

The volume ratio of the adhesive component (5) in the adhesive layers (2, 4) may be, for example, 55 volume% or more or 65 volume% or more, based on the total volume of the adhesive layers (2, 4), and may be 95 volume% or more. It may be % or less or 85 volume% or less.

The first conductive particles 6 exhibit a dendrite phase (also called a dendrite phase) and have one main axis and a plurality of branches branching two-dimensionally or three-dimensionally from the main axis. The first conductive particles 6 may be formed of a metal such as copper or silver, and may be, for example, silver-coated copper particles in which the copper particles are coated with silver.

The first conductive particles 6 may be known, and specifically, for example, ACBY-2 (Mitsui Kinzoku Kogyo Co., Ltd.), CE-1110 (Fukuda Kinzoku Hakuhun Kogyo Co., Ltd.), # It is available as FSP (JX Metal Co., Ltd.), #51-R (JX Metal Co., Ltd.), etc. Alternatively, the first conductive particles 6 can also be manufactured by a known method (for example, the method described in Patent Document 1 mentioned above).

The content of the first conductive particles 6 in the adhesive layers 2 and 4 (volume ratio of the first conductive particles 6 to the adhesive layers 2 and 4) is the total of the adhesive layers 2 and 4. Based on volume, it may be 2 volume% or more or 8 volume% or more, and may be 25 volume% or less or 15 volume% or less.

The second conductive particle 7 has a non-conductive nuclide and a conductive layer provided on the nuclide. The nuclear body is formed of a non-conductive material such as glass, ceramic, or resin, and is preferably formed of resin. Examples of the resin include acrylic resin, styrene resin, silicone resin, polybutadiene resin, and copolymers of monomers constituting these resins. The average particle diameter of the nucleoid may be, for example, 2 to 30 μm.

The conductive layer is formed of, for example, gold, silver, copper, nickel, palladium, or an alloy thereof. From the viewpoint of excellent conductivity, the conductive layer preferably contains at least one selected from gold, nickel, and palladium, more preferably contains gold or palladium, and even more preferably contains gold. The conductive layer is formed, for example, by plating the above-mentioned metal on a nuclear body. The thickness of the conductive layer may be, for example, 10 to 400 nm.

The average particle diameter of the second conductive particles 7 is preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less from the viewpoint of appropriately thinning the film. The average particle diameter of the second conductive particles 7 may be, for example, 1 μm or more. The average particle diameter of the second conductive particles 7 and the nuclei constituting it are measured by a particle size distribution measuring device (Microtrack (product name, Nikkiso Co., Ltd.)) using a laser diffraction/scattering method.

The content of the second conductive particles 7 in the adhesive layers 2 and 4 (volume ratio of the second conductive particles 7 to the adhesive layers 2 and 4) is the total of the adhesive layers 2 and 4. Based on volume, it may be 2 volume% or more or 5 volume% or more, and may be 20 volume% or less or 10 volume% or less.

The thickness of the adhesive layers 2 and 4 may be, for example, 5 μm or more, 10 μm or more, or 15 μm or more, and may be 40 μm or less, 30 μm or less, or 25 μm or less.

The metal layer 3 is, for example, titanium foil, stainless steel foil, nickel foil, copper foil, phosphor bronze foil, brass foil (brass foil), beryllium copper foil, nickel silver foil, 36 inbar foil, 42 alloy foil, PB permalloy foil. , PC permalloy foil, Kobar foil, Inconel foil, Hastelloy foil, monel foil, nichrome foil, constantan foil, manganin foil, aluminum foil, tantalum foil, molybdenum foil, niobium foil, zirconium foil, tungsten foil, gold foil, platinum. It is formed of foil, palladium foil, silver foil, silver lead foil, tin foil, lead foil, zinc foil, indium foil, lead-free solder foil, iron foil, etc.

The thickness of the metal layer 3 may be, for example, 5 μm or more, 25 μm or more, 30 μm or more, or 100 μm or more, and may be 500 μm or less, 300 μm or less, or 200 μm or less.

The thickness of the adhesive film 1 as a whole may be, for example, 40 μm or more, 80 μm or more, or 180 μm or more, and may be 600 μm or less, 400 μm or less, or 200 μm or less.

The adhesive film 1 is obtained, for example, by separately forming the first adhesive layer 2 and the second adhesive layer 4 and then laminating them on both sides of the metal layer 3, respectively. The first adhesive layer 2 and the second adhesive layer 4 are obtained, for example, by applying a paste-like adhesive composition onto a resin film such as a PET (polyethylene terephthalate) film and drying it. The paste-like adhesive composition is obtained, for example, by heating or dissolving a mixture containing the adhesive component 5, the first conductive particles 6, and the second conductive particles 7 in a solvent. As the solvent, for example, a solvent having a boiling point of 50 to 150°C at normal pressure is used.

The adhesive film 1 can be cured by, for example, curing the adhesive component 5 by heat treatment. The heating temperature is, for example, 40 to 250°C. The heating time is, for example, from 0.1 seconds to 10 hours.

The adhesive film 1 can be adhered to an adherend using a combination of heating and pressure. The heating temperature is, for example, 50 to 190°C. The pressure is, for example, 0.1 to 30 MPa. These heating and pressurization are performed, for example, in the range of 0.5 to 120 seconds.

The adhesive film 1 can be used as an adhesive to bond adherends of the same type to each other, and can also be used as an adhesive to bond adherends of different types (for example, adherends with different coefficients of thermal expansion) to each other. The adhesive film 1 is suitably used for connecting electronic elements.

Fig. 2 is a cross-sectional view of the main part schematically showing an example of connection between electronic members. As shown in FIG. 2 , the first electronic member 10 and the second electronic member 13 are electrically connected to each other via a connecting member (circuit connection material) 14.

The first electronic member 10 includes a first substrate 8 and a first electrode 9 formed on the main surface of the first substrate 8. The second electronic member 13 includes a second substrate 11 and a second electrode 12 formed on the main surface of the second substrate 11.

The first substrate 8 and the second substrate 11 may be formed of glass, ceramic, polyimide, polycarbonate, polyester, polyethersulfone, etc., respectively. The first electrode 9 and the second electrode 12 may be electrodes formed of gold, silver, copper, tin, aluminum, ruthenium, rhodium, palladium, osmium, iridium, platinum, indium tin oxide (ITO), etc., respectively. .

The connection member 14 includes a first hardened layer 15, a metal layer 3, and a second hardened layer 16 in this order from the first electronic member 10 side. The first cured layer 15 and the second cured layer 16 are each a cured product of the first adhesive layer 2 and the second adhesive layer 4 in the adhesive film 1 described above, and the adhesive component It contains the cured product 17 of (5), and first conductive particles 6 and second conductive particles 7 dispersed in the cured product 17. That is, the connection member 14 is formed by curing the adhesive film 1 described above.

In the adhesive film 1 according to the present embodiment, the metal layer 3 is provided between the first adhesive layer 2 and the second adhesive layer 4, thereby making the adhesive layers 2 and 4 thin, and the adhesive The entire film (1) can be thickened. Additionally, by using the first conductive particles 6 and the second conductive particles 7 together in the adhesive layers 2 and 4, suitable connection between electronic members can be realized. Therefore, even when the adhesive film 1 has a large thickness, it has excellent conductivity during low-pressure connection and can suppress leakage of the adhesive during connection. Additionally, this adhesive film 1 is also excellent in terms of reliability.

Example

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

(Preparation of solution A1)

50 g of phenoxy resin (manufactured by Union Carbide Co., Ltd., product name: PKHC, weight average molecular weight: 45000) was mixed with a mixed solvent of toluene (boiling point: 110.6°C) and ethyl acetate (boiling point: 77.1°C) (toluene:ethyl acetate in mass ratio). =1:1) to obtain a phenoxy resin solution with a solid content of 40% by mass. In this phenoxy resin solution, as radical polymerizable materials, urethane acrylate (manufactured by Negami Chemical Co., Ltd., product name: UN7700) and phosphoric acid ester dimethacrylate (manufactured by Kyoesia Chemical Co., Ltd., product name: Light) Ester P-2M) and 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane (manufactured by Nichiyu Co., Ltd., product name: Perhexa TMH) as a curing agent were used as a phenoxy resin: Solution A1 was obtained by mixing urethane acrylate:phosphoric acid ester dimethacrylate:curing agent at a solid mass ratio of 10:10:3:2.

As conductive particles B1 (first conductive particles), dendrite-like conductive particles (silver-coated copper particles, manufactured by Mitsui Kinzoku Kogyo Co., Ltd., product name: ACBY-2) were used.

(Production of conductive particle C1)

First, benzoyl peroxide was added as a polymerization initiator to a mixed solution of divinylbenzene, styrene monomer, and butyl methacrylate, and the mixture was heated with high speed and uniform stirring to perform a polymerization reaction to obtain a fine particle dispersion. This fine particle dispersion was filtered and dried under reduced pressure to obtain a block body, which is an aggregate of fine particles. Additionally, by pulverizing this block body, nuclei (resin particles) with different crosslinking densities and an average particle diameter of 20 μm were produced.

Next, a palladium catalyst (manufactured by Muromachi Technos Co., Ltd., product name: MK-2605) was supported on the surface of the nuclide, and the nuclide was activated with an accelerator (manufactured by Muromachi Technos Co., Ltd., product name: MK-370), 60 It was put into a mixed solution of nickel sulfate aqueous solution, sodium hypophosphite aqueous solution, and sodium tartrate aqueous solution heated to ℃, and the pre-electrolytic plating process was performed. This mixture was stirred for 20 minutes, and it was confirmed that hydrogen bubbling had stopped. Next, a mixed solution of nickel sulfate, sodium hypophosphite, sodium citrate, and a plating stabilizer was added, stirred until the pH was stabilized, and a post-electrolytic plating process was performed until hydrogen foaming stopped. Subsequently, the plating solution was filtered, the filtrate was washed with water, and then dried in a vacuum dryer at 80°C to produce nickel-plated conductive particles C1 (second conductive particles).

[Example 1]

<Production of adhesive film>

45 parts by volume of conductive particles B1 and 15 parts by volume of conductive particles C1 were dispersed in 100 parts by volume of solution A1 to obtain a mixed solution. The obtained mixed solution was applied onto a fluororesin film with a thickness of 80 μm, the solvent was removed by hot air drying at 70° C. for 10 minutes, and the adhesive composition in the form of a film with a thickness of 20 μm formed on the fluororesin film (first adhesive layer and A second adhesive layer) was obtained.

Next, the first adhesive layer was laminated on one side of a 25㎛ thick copper foil (Kunshan Hanpoom Electronics, product name: XPH0A 01-025). Additionally, an adhesive film with a thickness of 65 μm was obtained by laminating a second adhesive layer on the other side of the copper foil surface.

The properties when the obtained adhesive film was used for a connection member were evaluated in the procedure shown below.

<Evaluation of conductivity during low voltage connection>

As shown in Figures 3 (a) and (b), the adhesive film 31 obtained by cutting the obtained adhesive film into 6 mm x 6 mm is placed approximately in the center of the copper foil 32 of 6 mm x 50 mm. , it was attached by heating and pressurizing (50°C, 0.1 MPa, 2 seconds) using BD-07 manufactured by Ohashi Seisakusho Co., Ltd. Subsequently, as shown in FIGS. 3(c) and 3(d), an aluminum foil 33 of 50 mm x 6 mm was prepared. Aluminum foil 33 was placed on the laminate of copper foil 32 and adhesive film 31 to cover adhesive film 31, and then heated and pressed (150°C, BD-07, manufactured by Ohashi Seisakusho Co., Ltd.). 0.1 MPa, 10 seconds) to obtain a mounting body for evaluation of conductivity during low-voltage connection. An ammeter and a voltmeter were connected to the obtained mounting body as shown in FIG. 4, and the connection resistance (initial) was measured by the four-terminal method. The results are shown in Table 1.

<Evaluation of leakage suppression of adhesive components>

First, when manufacturing a mounting body using the same procedure as in <Evaluation of conductivity during low-voltage connection> above, the connection resistance (initial) measured in the same manner as <Evaluation of conductivity during low-voltage connection> for the resulting mounting body is 0.20. The pressure required to become Ω (the pressure when the adhesive film 31 is overlapped and heated and pressed with respect to the laminate of the copper foil 32 and the adhesive film 31) P (MPa) was calculated.

Next, the outflow amount of the adhesive component was evaluated by the procedure shown below. That is, the adhesive film obtained above was cut into squares of 3 mm x 3 mm for each fluororesin film to obtain an adhesive film with a fluororesin film. The adhesive film side of the fluorine resin film-equipped adhesive film was placed approximately in the center on the cover glass so that it was in contact with each cover glass (product number C018181) made by Matsunami Glass, and heated and pressurized with BD-07 made by Ohashi Seisakusho Co., Ltd. (60 °C, 0.1 MPa, 2 seconds), the fluororesin film was peeled off. Subsequently, one more sheet of the same cover glass was placed on the adhesive film, and it was heated and pressed (130°C, pressure P (MPa) calculated above, for 10 seconds) with BD-07, manufactured by Ohashi Seisakusho Co., Ltd. . Using a scanner and Photoshop (registered trademark), the area [A] of the peeled fluororesin film and the area [B] of the adhesive film after heating and pressing were measured as the number of pixels, and the outflow amount was calculated according to the formula below. The results are shown in Table 1.

Outflow amount (%)=([B]/[A])×100

<Evaluation of reliability>

As shown in Figures 3 (a) and (b), the adhesive film 31 obtained by cutting the obtained adhesive film into 6 mm x 6 mm is placed approximately in the center of the copper foil 32 of 6 mm x 50 mm. , it was attached by heating and pressurizing (50°C, 0.5 MPa, 2 seconds) using BD-07 manufactured by Ohashi Seisakusho Co., Ltd. Subsequently, as shown in FIGS. 3(c) and 3(d), an aluminum foil 33 of 50 mm x 6 mm was prepared. Aluminum foil 33 was placed on the laminate of copper foil 32 and adhesive film 31 to cover adhesive film 31, and then heated and pressed (150°C, BD-07, manufactured by Ohashi Seisakusho Co., Ltd.). 0.5 MPa, 10 seconds) to obtain a mounting body for reliability evaluation.

An ammeter and a voltmeter were connected to the obtained mounting body as shown in FIG. 4, and the connection resistance (initial) was measured by the four-terminal method. In addition, using TSA-43EL manufactured by Espec Corporation, temperature was maintained at -20°C for 30 minutes, temperature was raised to 100°C over 10 minutes, temperature was maintained at 100°C for 30 minutes, and temperature was lowered to -20°C over 10 minutes. After performing a heat cycle test in which the heat cycle was repeated 500 times on the mounting body, the connection resistance (after the heat cycle test) was measured in the same manner as above. The results are shown in Table 1.

[Example 2]

An adhesive film was produced and evaluated in the same manner as in Example 1, except that the thicknesses of the first adhesive layer and the second adhesive layer were each changed to 25 μm.

[Example 3]

Except that the thickness of the metal layer was changed to 30 μm, the adhesive film was produced and evaluated in the same manner as in Example 1.

[Comparative Example 1]

In the first adhesive layer and the second adhesive layer, the adhesive film was produced and evaluated in the same manner as in Example 1, except that conductive particles B1 (first conductive particles) were not used.

[Comparative Example 2]

In the first adhesive layer and the second adhesive layer, the adhesive film was produced and evaluated in the same manner as in Example 1, except that the conductive particles C1 (second conductive particles) were not used.

[Comparative Example 3]

The adhesive film was produced and evaluated in the same manner as in Example 1, except that the adhesive film containing only the adhesive layer (thickness 65 μm) described above was produced without providing a metal layer.

1: Adhesive film
2: First adhesive layer
3: Metal layer
4: Second adhesive layer
6: first conductive particle
7: Second conductive particle

Claims (5)

A first electronic member having a first substrate and a first electrode formed on the main surface of the first substrate, a second electronic member having a second substrate and a second electrode formed on the main surface of the second substrate, the first electrode and An adhesive film used to connect the second electrodes facing each other,
A first adhesive layer, a metal layer, and a second adhesive layer are provided in this order,
Each of the first adhesive layer and the second adhesive layer,
First conductive particles that are dendrite-like conductive particles,
An adhesive film which is an electrically-conductive particle other than the said 1st electrically-conductive particle, and contains a 2nd electrically-conductive particle which is an electrically-conductive particle which has a non-conductive nuclide and a conductive layer provided on the nuclide. The adhesive film according to claim 1, wherein the conductive layer contains at least one material selected from the group consisting of gold, nickel, and palladium. The adhesive film according to claim 1 or 2, wherein the metal layer has a thickness of 25 μm or more. The adhesive film according to claim 1 or 2, wherein the first adhesive layer has a thickness of 30 μm or less. The adhesive film according to claim 1 or 2, wherein the second adhesive layer has a thickness of 30 μm or less.

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